CVE-2026-90315
Description
In the Linux kernel, the following vulnerability has been resolved: PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers Currently, the legacy I/O and memory sysfs handlers do not check security_locked_down(LOCKDOWN_PCI_ACCESS), leaving the legacy_io and legacy_mem files unprotected when the kernel is locked down. Commit eb627e17727e ("PCI: Lock down BAR access when the kernel is locked down") added the check to pci_write_config(), pci_mmap_resource(), and pci_write_resource_io() to prevent userspace from programming DMA-capable hardware that could be used to modify kernel code, but did not cover the legacy handlers. As a result, root can still write arbitrary I/O ports and map the legacy I/O and memory spaces while the kernel is locked down, which is the same capability the lockdown is meant to remove. Add the same check to pci_write_legacy_io(), pci_mmap_legacy_mem(), and pci_mmap_legacy_io(). These generic handlers cover both architectures that define HAVE_PCI_LEGACY (such as Alpha and PowerPC). [bhelgaas: add Link]
How to fix
- Linux Linux3556caa31a2bfbc22c11b812fd4ed8851c2d7bff, cd07aef510ac6a2873e01f9ddddc5492490b0067, 747b9bbbbdfdee51aee2456388f9b94b5086de4d or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | eb627e17727ebeede70697ae1798688b0d328b54 ≤ v < 3556caa31a2bfbc22c11b812fd4ed8851c2d7bff, eb627e17727ebeede70697ae1798688b0d328b54 ≤ v < cd07aef510ac6a2873e01f9ddddc5492490b0067, eb627e17727ebeede70697ae1798688b0d328b54 ≤ v < 747b9bbbbdfdee51aee2456388f9b94b5086de4d, 5.4 | 3556caa31a2bfbc22c11b812fd4ed8851c2d7bff, cd07aef510ac6a2873e01f9ddddc5492490b0067, 747b9bbbbdfdee51aee2456388f9b94b5086de4d |
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